I did have this problem in the past. I fixed it by switching to a Microsoft Natural keyboard (the $40 one). That got rid of the problem for me after about three

I did have this problem in the past. I fixed it by switching to a Microsoft Natural keyboard (the $40 one). That got rid of the problem for me after about three days. At first I thought the improvement was due to the ergonomic form of the keyboard, but after using my MacBook Pro's built-in keyboard for months with no pain, I now think that my problem was just that my original cheap, foam-sprung keyboard was just awful for typing. So maybe the answer is to just get a better keyboard. Additionally, posture and angle of forearms to the keyboard surface is also a factor with any keyboard. Your forearms should be parallel to the ground and your keyboard flat, at least that's what works for me. If your chair is too low this might be forcing you to contort your hands in order to type. For example, my MacBook Pro's keyboard works fine for me, but the external Apple wireless keyboard (with the same type of keys) causes RSI very quickly. Since the keys are essentially the same on both, I'm sure that this is because the external keyboard is angled (higher in back where the batteries go) while the laptop's keyboard is flat.